531,747,660 BCE

499,539,992 BCE

451,672,886 BCE

A Type-40 TARDIS arrives on Earth, carrying the Time Lords called the Doctor, Susan, and Stoyn. Stoyn teams up with aliens manipulating life's development on Earth. The Doctor and Susan's interference results in all parties getting stuck in suspended animation on the moon for millions of years.1

350,400,099 BCE

The powerful entity Cthulhu arrives on Earth. After a skirmish with various other entities, it settles on the island of R'lyeh.

255,285,459 BCE

The Manraloth attempt to forge a connection between themselves and the species they had come to know that had evolved to other planes. This attempt results in a massive psionic feedback that kills nearly all sapient life in the Milky Way Galaxy. In the aftermath, the surviving Manraloth, including Giriaenn, suspend themselves in states of zero entropy.2

225,616,125 BCE

The race called Nuwali are hired by the extra-dimensional Beyonders to create biological preserves throughout the cosmos. Their first attempt is on Earth, where they close off a tropical region populated with dinosaurs. This region will someday be known as the Savage Land.

175,806,841 BCE

The Great Chaos War between the Lumina and the Myndai ends in a battle over the planet Earth. The Myndai's base is buried, and the inhabitants enter suspended animation. The Lumina set up an outpost on Earth in preparation for the day the Myndai awaken.

139,157,807 BCE

The Doctor (fifth incarnation), Nyssa (21), and Tegan Jovanka (21) travel on a Concorde plane from 1982 to this point. The Master (Tremas possession) is forced into a truce with the Doctor so as to leave this era.3

100,000,357 BCE

The creature later known as It and Pennywise arrives on Earth. Mike Hanlon and Richie Tozier (both 11/1958) are transported to this time due to a smoke hole ceremony. They witness the arrival and then disappear.4

75,001,978 BCE

75,001,966 BCE

The galactic tyrant Xenu (12), with the help of a cabal of psychiatrists, gathers billions of his confederacy's citizens to Earth. Binding them to volcanoes, he kills them through the detonation of hydrogen bombs. The massive number of non-native deaths causes these alien essences to be trapped, and become malevolent spirits called thetans. Xenu makes the thetans watch a long movie.5

67,105,946 BCE

64,105,940 BCE

A time machine carrying Scrooge McDuck (121), Launchpad McQuack (26), and triplets Huey, Dewey, and Louie Duck (all three 48) (all 1988 CE), arrives in this era. Scrooge inadvertently saves the life of the young Ahgguu "Bubba"7 (6), causing Bubba to bond with him. After Scrooge marks a cave so as to have prior claim, they depart, with Bubba and his pet Triceratops, Tootsie, stowing away.8

64,791,386 BCE

The Silurian Alliance is formed between the various sapient reptilian races of Earth.

64,780,203 BCE

64,780,149 BCE

September 25. A freighter carrying Adric (17), traveled back from 2526 CE, and followed by the TARDIS carrying the Doctor (fifth incarnation), Nyssa (21), and Tegan Jovanka (21), crashes into the planet Earth, causing the Cretaceous-Paleogene Extinction event. Adric dies upon the freighter's impact.9

With the impact, the Silurian civilization fractures. The Voth species creates starships and flee the planet. The D'ryze, Namuz, and Zewb go into suspended animation beneath the planet's surface. Vastra (54) is among those that goes to sleep.

At the same time as the impact, a fragment of a mindless evil entity crashes to Earth after severe temporal displacement.10

64,780,145 BCE

Mysto-temporal energies unsettled by the freighter impact result in a valley region on Earth becoming extremely fertile and lush. The temporal energies cause species that were long extinct in this era to spontaneously appear through rifts. Individuals and groups of numerous animal species, including the anachronistic ones, gain sapience in the region around the valley. The animals begin a trek toward the valley, motivated by pseudo-telepathic projection by the plant species within.11

64,780,075 BCE

64,780,072 BCE

August 6. A great earthquake devastates the land east the Great Valley. The day it strikes, the young dinosaurs Littlefoot (4) and Cera (4) are nearly eaten by a tyrannosaur. Littlefoot's mother battles the predator, suffering fatal injuries. Littlefoot and Cera are separated from their families by a huge crevasse. After Littlefoot's mother dies, he gets a Tree Star (mystical leaf), which sets him off alone on his quest to reach the Great Valley.15

August 7. Littlefoot meets the young Saurolophus Ducky (3) and the young pteranodon Petrie (4), also separated from their families by the earthquake. They also find a stegosaur egg, which hatches. Ducky names the large infant Spike. They are subsequently joined by Cera.16

August 9. Littlefoot and his group manage to drown his mother's killer, and find their way to the Great Valley.17

7. Bubba is a "cave duck", meaning he was a sort of evolutionary predecessor to the duck people of the DuckTales universe. For this timeline there are no natural evolutionary predecessors to the Anthropomorphs, so Bubba's origin has to be adjusted. I decided he would be an alien that happened to look Anthro duck-like, and an orphan, explaining his lack of education despite presumably coming from a space-capable world. I also adjusted the time-traveling from the 1000000 BCE dating Launchpad claimed to one in which triceratops actually roamed the Earth.

11. This is an attempt to explain The Land Before Time and other talking dinosaur stories that don't deal directly with the end of the age of dinosaurs. It also works with the various anachronisms that tend to pop up with dinosaur stories, as they often have dinosaurs that lived in different eras coexisting.

12. At the time of the film's debut, the brontosaurus was considered a valid species of dinosaur. It is apparently so again at the time of this writing, with it having been considered a misidentified Apatosaurus in the interim.